Room air cleaner

ABSTRACT

A portable air cleaner designed to remove particles and unwanted gases from a room to provide for a healthier and cleaner environment. The portable air cleaner includes a high air volume circulating design and operates quietly and efficiently. The air exhaust of the air cleaner includes a plurality of arcuate vanes radiating outwardly from the interior of the air cleaner. The vanes are disposed in a non-symmetrical arrangement the air exhaust to reduce pressure drop and to minimize operation noise.

INCORPORATION BY REFERENCE

U.S. Pat. Nos. 5,248,323; 5,515,573; 5,593,479; 5,603,741; 5,641,343;5,651,811; 5,658,362; and 5,837,020 are incorporated herein toillustrate the type of vacuum cleaner and/or air cleaner and the type offilter system in which the present invention can be used, and topreclude the necessity of repeating structural details relating to suchfilter systems, vacuum cleaners and air cleaners.

The present invention relates to the art of air filter systems and moreparticularly to a high efficiency, low noise, portable room air cleaner.The invention is particularly applicable to a portable canister type aircleaner and will be described with particular reference thereto;however, the invention has much broader applications and may be used invacuum cleaners and/or to filter air in other environments by employingthe novel air filtering arrangement as contemplated in the presentinvention.

BACKGROUND OF THE INVENTION

As more and more people move to urban environments, there is an everincreasing need to provide a clean air environment at home and in thework place. In urban areas, where pollution levels sometimes exceedmaximum values set by the EPA, the need for a clean air environmentbecomes even more apparent. In view of the posed hazards these pollutedenvironments create, the public has demanded a means for removingpollutants from the environment to provide a healthy environment forboth living and working. Furthermore, many of these particles in the aircan act as irritants and/or increase or aggravate a person's allergies.Airborn pollutants can also contribute to respiratory infections andillnesses which can be hazardous to individuals with respiratoryproblems. Particles in the air can create problems such as burning eyes,nose and throat irritation, contributing to headaches and dizziness,which can result in coughing and sneezing. Furthermore, these particlescan include various types of spores, dust mites, microorganisms, such asbacteria and/or viruses, and/or other types of harmful particles whichmay cause serious illness or infection to a person.

In an effort to reduce the number of particles from the air and/or otherenvironments, many homes, offices, and buildings have incorporated acentral filtering system to remove particles entrained in the air.Unfortunately, these systems are very expensive and/or do not removemany of the small particles which can be the most hazardous andirritable to persons, such as spores, micro-organisms, such as bacteriaand/or viruses, dust mites and some harmful chemicals. Typically, thesefiltering systems only remove about 300,000 particles out of about 20million particles which flow into the filter medium. The smallparticles, which make up a majority of the particles in the air, freelypass through these conventional filter systems.

Specialized filters have been developed to remove many of the smallparticles in the air. Such filters are known as HEPA filters, whichstands for High Efficiency Particle Air Filters, which, by governmentstandards, are filters with a minimum efficiency of 99.97%. The industrydefines HEPA filters as those filters which are efficient in removing99.97% the airborn particles the size of 0.3 micron or larger. Suchfilters are commonly used in ultra clean environments such as in alaboratory, in electronic and biologically clean rooms, in hospitals andthe like. These filters have recently been incorporated in air filtersfor business and individual use.

In U.S. Pat. No. 4,629,482 a portable HEPA room air cleaner isdisclosed. The air cleaner incorporates a cylindrical HEPA filter andthe filter is mounted within the filter housing having an air dischargeat its base. A centrifugal fan is incorporated in the housing to drawair through the filter and discharge air at the base of the housing. Dueto the configuration of the air cleaner, it is necessary to space thebase of the apparatus from the main housing. Such a configuration alsorequires that the apparatus be designed somewhat larger than someconsumers may desire. The discharge of air at the base of the unitresults in the recirculation of particles which have already settled onthe floor. Such recirculation of settled particles can result inincreased particle irritation. The air cleaner does not incorporate agas filter to remove irritable or noxious gas from the air.

In U.S. Pat. No. 5,435,817, another type of portable HEPA room aircleaner is disclosed. This unit is cylindrical in shape and includes abase discharge. A centrifugal fan is used to draw air into the top ofthe unit and discharge filtered air at the base of the unit. The unitincorporates an outer deflector wall to radially discharge air at thebottom of the unit, such that the exhaust air is channeled generallycircumferentially about the base of the unit. The discharged air at thebase of the unit results in the redistribution of settled particles backinto the air. The air cleaner is also absent any mechanism for removingunwanted gases in the air.

Assignee's U.S. Pat. No. 5,641,343 discloses an improved air cleanerdesign which discharges purified air near the top of the unit to reducerecirculation of settled particles. The air cleaner also incorporates aninternal air flow design which reduces pressure drop through the aircleaner thereby improving the efficiencies of the air cleaner. The airfilter further incorporates an improved filtering agent to remove moreparticles as compared to standard HEPA filters. The efficiencies ofstandard HEPA filters are all based upon 0.3 micron size particles.Historically, it was believed that particles about 0.3 micron in sizewere the most difficult to remove from the air. However, recent particlefiltration testing has shown that particles the size of about 0.1 micronare the most difficult to remove from the air. Standard HEPA filters donot efficiently remove such small particles and allow such particles tofreely pass through the filter medium. An analysis of these smallparticles has shown that the particles do not naturally fall out of theair, but instead remain entrained in the air by constantly bouncing offother particles in the air (i.e. Browning effect). These small particleshave also been found to deviate from the air flow thus making suchparticles even more difficult to remove from the air. The improvedparticle filter used in U.S. Pat. No. 5,641,343 overcomes this particlefiltration problem by incorporating a filter which can remove at leastabout 99.98% of particles about 0.1 micron in size. The filter systemcan also include a gas filter to remove unwanted gases from the filteredair.

Although Assignee's air filter disclosed in U.S. Pat. No. 5,641,343greatly improves air purification technology, additional improvements inair purification efficiencies were still demanded. During the airpurification process, the air intake section is preferably the largestsurface area component of the air cleaner so as to maximize the size ofthe air filter and volume of air to be purified. However, when the airintake is enlarged, the air purification unit must be enlarged, sincethe reduction in size of the air exhaust will cause an increase inpressure drop and significant reductions in efficiencies. In order toovercome the increased pressure drop, larger motors must be used whichare more costly, noisier and energy consuming. In addition to the noisecaused by the increased motor size, the velocity of air through thesmaller air exhaust region results in additional noise during operation.To address this problem, Assignee invented an improved air cleaner whichis disclosed in U.S. Pat. No. 5,837,020. The air cleaner disclosed inU.S. Pat. No. 5,837,020 includes an air exhaust having a plurality ofarcuate shaped vanes. The vanes all have the same shape and size and aresymmetrically oriented about the air exhaust. The ends of each vane arespaced the same distance from the blower fan to effectively draw airfrom the blower fan. The drawn air is directed outwardly along theoutwardly radiating arcuate vanes. The use of the arcuate vanes overcomethe pressure drop problems associated with a smaller air exhaust regionthereby allowing larger volumes of air to be expelled in a given surfacearea. As a result, the size of the air exhaust can be reduced, which inturn can reduce the size of the air cleaner. Furthermore, a larger motordoes not need to be used for a smaller air exhaust, since comparablepressure drops are obtained, even though the vane design air exhaustoccupies a smaller area than a mesh design air exhaust.

Although the air cleaner disclosed in U.S. Pat. No. 5,837,020 is asignificant improvement over prior air cleaner designs, the air cleaner,in some instances, produces vibrational noises during operation. Much ofthis noise is attributed to the harmonics of the vanes as the filteredair is expelled through the vanes. Therefore, there is a need for animproved air exhaust design which incorporates the use of vanes havingreduced vibration tendencies during the operation of the air cleaner.

SUMMARY OF THE INVENTION

The invention relates to compact portable room air cleaner and will bedescribed with particular reference thereto; however, it will beappreciated that the air cleaner can be used in general industriallevels and in other environments, wherein it is desirable to remove verysmall particles and/or undesirable gases from the environment. Inaddition, the features of the room air cleaner can be incorporated intoa vacuum cleaning system.

In accordance with the principal aspect of the present invention, thereis provided a portable air cleaner which includes a housing having aninner chamber. The exterior of the housing includes an air exhaust andan air intake. In one embodiment, the air intake is located below theair exhaust. In one aspect of this embodiment, the air intake is locatedat or near the base of the air cleaner to draw air into the air cleanerat or near the base of the air cleaner. In another specific aspect ofthis embodiment, the air exhaust is located at or near the top of theair cleaner to expel filtered air at or near the top of the air cleaner.The air being drawn into the air cleaner at or near the housing basedoes not re-blow settled particles back into recirculation in the room.If any settled particles are disturbed, these particles are immediatelydrawn into the air cleaner and filtered out of the air. The air expelledby the air exhaust positioned at or near the top of the housing isdistanced from the floor where settled particles exist, thus theexpelled air causes little, if any, settled particles to be recirculatedin the room. In another embodiment, the air intake and air exhaust arelocated about the complete peripheral edge of the housing so as to drawin and expel air essentially around the complete peripheral surface ofthe housing. This design of the air intake and air exhaust maximizes thesurface area in which the air can be drawn in and expelled from the aircleaner. As a result, large volumes of air can be filtered by the aircleaner. Furthermore, the velocity of the air into and out of the aircleaner is reduced due to the large surface area of the air intake. Thereduced velocity of the air into the air cleaner reduces problems ofstirring settled particles near the air cleaner. The design of the aircleaner to both draw and expel air around the periphery of the housingalso allows the air filter to be positioned in various places in a roomwithout concern for blocking the air flow into the air intake or out ofthe air exhaust. In yet another embodiment, the surface area on theexterior of the housing for the air intake is greater than the surfacearea on the exterior of the housing for the air exhaust. In stillanother embodiment, the air exhaust includes a plurality of arcuateshaped vanes. In still yet another embodiment, the vanes are positionedin the air exhaust to minimize vibrational noise during the operation ofthe air cleaner. In a further embodiment, the vanes are positioned inthe air exhaust to increase air efficiencies and reduce pressure dropduring the operation of the air cleaner. In one aspect of thisembodiment, the air exhaust includes a blade that causes filtered air tobe expelled from the air cleaner. Each of the vanes in the air exhausthave an inner or leading end positioned closely adjacent to theperiphery of the blade. The inner or leading end of the vane is spacedfrom the blade a distance to effectively draw filtered air from theblade. Once the filtered air is drawn from the blade, the filtered airis directed outwardly along the outwardly radiating arcuate vanes untilexpelled from the outer periphery of the air exhaust. In yet a furtherembodiment, the vanes are positioned in the air exhaust to reduce theamount of noise generated by the air cleaner during operation. Humanstypically cannot hear sound that has a wave length of more than 20 KHz.The air exhaust, and more particularly, the vanes in the air exhaust aredesigned and/or arranged in the air exhaust to reduce the amount ofsound generated during the operation of the air exhaust that has a wavelength of less than about 20 KHz. In one aspect of this embodiment, thevanes in the air exhaust are designed and/or arranged in the air exhaustto reduce the amount of sound generated during the operation of the airexhaust that has a wave length of less than about 18 KHz.

In accordance with another aspect of the present invention, one or morevanes in the air exhaust are oriented, configured and/or designeddifferently from one or more adjacent vanes such that the harmonics ofone or more vanes during the operation of the air cleaner is different.In one embodiment, one or more vanes in the air exhaust are notsymmetrically oriented with respect to the periphery of the air exhaust.In one aspect of this embodiment, at least one vane has an outer or backend positioned at or close to the periphery of the air exhaust such thatthe outer or back end is spaced a different distance from the outer orback end of one or more adjacent vanes. In another aspect of thisembodiment, the distance between the outer or back end of the adjacentpositioned vanes progressively increases. In one particular design ofthis aspect of this embodiment, the air exhaust includes four vanes. Theperiphery of the air exhaust is substantially circular. Theprogressively increased spacing of the outer or back ends of theadjacently positioned vanes is 81.75°, 89.75°, 92.75° and 95.75°. As canbe appreciated, other angles of separation can be used. By having one ormore vanes being not symmetrically oriented with respect to theperiphery of the air exhaust, the harmonics of two or more vanes aredifferent during operation, thereby interfering with an additivevibrational effect. As a result, the amount of vibration of the vanesduring the operation of the air cleaner is significantly reduced,thereby reducing the vibrational noise during operation of the aircleaner. In addition, the air pressure between differently positionedvanes varies during the operation of the air cleaner. It has been foundthat this variable air pressure increases the efficiency of filtered airbeing expelled by the air cleaner and also results in reduced pressuredrop. In another embodiment, one or more vanes in the air exhaust arenot symmetrically oriented about the blade in the air exhaust. In oneaspect of this embodiment, at least one vane has an inner or leading endpositioned about the blade such that the inner or leading end is spaceda different distance from the inner or leading end of one or moreadjacent vanes. In another aspect of this embodiment, the inner orleading end of the adjacently positioned vanes progressively increases.In one particular design of this aspect of this embodiment, the airexhaust includes four vanes. The blade in the air exhaust issubstantially circular. The progressively increased spacing of the inneror leading ends of the adjacently positioned vanes is 81.75°, 89.75°,92.75° and 95.75°. As can be appreciated, other angles of separation canbe used. By having one or more of the inner or leading ends of theadjacent vanes positioned at different distances with respect to oneanother, the harmonics of two or more vanes are different duringoperation thereby reducing the amount of vibration of the vanes duringoperation, reducing the amount of vibrational noise during operation,reducing the pressure drop through the room cleaner, and increasing theair filtering efficiencies of the room cleaner. In still anotherembodiment, the width of the inner or leading end of at least one vaneis different from the width of the inner or leading end of one or moreadjacent vanes. By having the different widths of one or more of theinner or leading ends of adjacent vanes, the harmonics of two or morevanes are different during operation thereby reducing the amount ofvibration of the vanes during operation, reducing the amount ofvibrational noise during operation, reducing the pressure drop throughthe room cleaner, and increasing the air filtering efficiencies of theroom cleaner. In still yet another embodiment, the distance of the inneror leading end of at least one vane from the blade is different from thedistance of the inner or leading end of one or more adjacent vanes fromthe blade. In one aspect of this embodiment, the inner or leading end ofeach vane is spaced within about one inch of the blade. Typically, theinner or leading end of each vane is spaced about 0.05-0.4 inch from theblade. By having the different distances of one or more of the inner orleading ends of adjacent vanes from the blade, the harmonics of two ormore vanes are different during operation thereby reducing the amount ofvibration of the vanes during operation, reducing the amount ofvibrational noise during operation, reducing the pressure drop throughthe room cleaner, and increasing the air filtering efficiencies of theroom cleaner. In a further embodiment, the radius of curvature of atleast a portion of one or more vanes is different from the radius ofcurvature of at least a portion of one or more adjacent vanes. By havingthe radius of curvature of at least a portion of one or more vanesdifferent from the radius of curvature of one or more adjacent vanes,the harmonics of two or more vanes are different during operation,thereby reducing the amount of vibration of the vanes during operation,reducing the amount of vibrational noise during operation, reducing thepressure drop through the room cleaner, and increasing the air filteringefficiencies of the room cleaner. In yet a further embodiment, at leastone vane has a different length from at least one or more adjacentvanes. By having a length of one or more vanes different from the lengthof one or more adjacent vanes, the harmonics of two or more vanes aredifferent during operation, thereby reducing the amount of vibration ofthe vanes during operation, reducing the amount of vibrational noiseduring operation, reducing the pressure drop through the room cleaner,and increasing the air filtering efficiencies of the room cleaner. Instill a further embodiment, the inner or leading end of one or morevanes is sloped differently from the inner or leading end of one or moreadjacent vanes. The sloped surface of the inner or leading end of one ormore vanes performs several functions such as reducing air noise andincreasing the efficiency by which the air is drawn from the blade. Asthe inner or leading end of a vane is positioned closer to the blade ofthe blower fan, more air is drawn away from the blade by the vane. Theincreased amount of drawn air from the blade increases the efficiency towhich the blower fan draws air into the air cleaner and expels thefiltered air. However, the closer the leading end of the vane ispositioned to the blade during operation, the louder the air cleaneroperates. The increased noise levels are caused by the high velocity aircontacting the inner or leading end of the vane and causing a whistlingsound. In addition, the high velocity air can cause the vane to vibratewhich also results in noise. The vibration and whistling is reduced orsignificantly eliminated by increasing the space of the inner or leadingend of the vane from the blade. However, increasing of the spacing ofthe vane inner or leading end from the blade reduces the efficiency atwhich the air is drawn from the blade, thus reducing the amount of airdrawn into the air cleaner. By sloping the inner or leading end of thevane, the amount of whistling noise and vibration of the vane issignificantly reduced when the inner or leading end of the vane ispositioned close to the blade. As a result, the inner or leading end canbe placed closer to the blade to increase air withdrawal efficiencieswithout increasing operation noise. The use of a sloped surface vane ascompared to a straight surface vane has also been found to moreefficiently draw air from the blade during operation of the air cleaner,thus further increasing the efficiencies of operation. In one aspect ofthis embodiment, the sloped inner or leading end of at least one vaneslopes from the top to the bottom of the vane. In another aspect of thisembodiment, the inner or leading end of at least one vane slopes fromthe bottom to the top of the vane. In still another aspect of thisembodiment, the sloped angle of the inner or leading end of the vane isabout 10-75°. In operation, the sloped angle is typically about 20-40°.In yet another aspect of this embodiment, the sloped surface is a linearor straight surface. In still yet another aspect of this embodiment, thesloped surface is an arcuate or curved surface. In still a furtheraspect of this embodiment, the angle of slope of the inner or leadingend of at least one vane is different from the angle of slope of theinner or leading end of one or more adjacent vanes. By having differentangles of slope of one or more of the inner or leading ends of adjacentvanes, the harmonics of two or more vanes are different during operationthereby reducing the amount of vibration of the vanes during operation,reducing the amount of vibrational noise during operation, reducing thepressure drop through the room cleaner, and increasing the air filteringefficiencies of the room cleaner. In yet a further aspect of thisembodiment, the length of the sloped region of the inner or leading endof at least one vane is different from the length of the sloped regionof the inner or leading end of one or more adjacent vanes. By havingdifferent lengths of sloped regions of one or more of the inner orleading ends of adjacent vanes, the harmonics of two or more vanes aredifferent during operation thereby reducing the amount of vibration ofthe vanes during operation, reducing the amount of vibrational noiseduring operation, reducing the pressure drop through the room cleaner,and increasing the air filtering efficiencies of the room cleaner. Instill a further embodiment, the rigidity profile of at least one vane isdifferent from the rigidity profile of one or more adjacent vanes. Inone aspect of this embodiment, the rigidity of one or more vanes isaltered by increasing or decreasing the thickness of the vane over atleast a portion of the vane. The differing vane thickness will cause thevane to vibrate differently from other vanes as filtered air passesthrough the vanes during operation of the air cleaner. In another aspectof this embodiment, the rigidity of one or more vanes is altered bychanging the composition of the vane over at least a portion of thevane. The differing vane composition will cause the vane to vibratedifferently from other vanes as filtered air passes through the vanesduring operation of the air cleaner. By having different rigidityprofiles of one or more adjacent vanes, the harmonics of two or morevanes are different during operation thereby reducing the amount ofvibration of the vanes during operation, reducing the amount ofvibrational noise during operation, reducing the pressure drop throughthe room cleaner, and increasing the air filtering efficiencies of theroom cleaner. In still yet a further embodiment, the inner or leadingend of the vane has a tapered edge. The tapered edge further reducesoperation noise and increases air withdrawal efficiencies from theblower fan. In one aspect of this embodiment, the inner or leading endof at least one vane has a tapered edge and the inner or leading end ofat least one vane does not have a tapered edge. By having one or movevanes with tapered edges and one or more vanes without tapered edges,the harmonics of two or more vanes are different during operation,thereby reducing the amount of vibration of the vanes during operation,reducing the amount of vibrational noise during operation, reducing thepressure drop through the room cleaner, and increasing the air filteringefficiencies of the room cleaner. In another aspect of this embodiment,the thickness of the tapered edge of an inner or leading end of at leastone vane is different from the thickness of a tapered edge of an inneror leading end of at least one vane. By having one or more vanes withtapered edges of differing thicknesses, the harmonics of two or morevanes are different during operation, thereby reducing the amount ofvibration of the vanes during operation, reducing the amount ofvibrational noise during operation, reducing the pressure drop throughthe room cleaner, and increasing the air filtering efficiencies of theroom cleaner. As can be appreciated with respect to these embodimentsand aspects of these embodiments, two or more combinations of theseembodiments and aspects of these embodiments can be used in the aircleaner to reduce the vibrational noise and increase the airefficiencies during operation of the air cleaner.

In yet another aspect of the present invention, the use of a mesh screenabout the outer periphery of the air exhaust can be eliminated. The useof a typical mesh type screen causes a significant pressure drop as thefiltered air passes through the multitude of openings in the screen. Theelimination of the use of a traditional mesh design and the use of thenew vane design overcomes the pressure drop problems, thereby allowinglarger volumes of air to be expelled in a given surface area. Therefore,a smaller size air exhaust can be used for a given pressure drop andvolume of air expulsion as compared to a mesh screen air exhaust design.As a result, the size of the air exhaust can be reduced, which in turncan reduce the size of the air cleaner. Furthermore, a larger motor doesnot need to be used for a smaller air exhaust since comparable pressuredrops are obtained even though the air exhaust occupies a smaller areathan an air exhaust which includes a screen.

In accordance with a further aspect of the present invention, the airexhaust includes one or more air guides positioned between two or morevanes. The air guides assist in distributing the filtered air as it isexpelled from the air cleaner, thereby reducing the air velocity fromthe air cleaner via a diffusion effect. The filtered air leaving the airexhaust may be expelled in a jet stream matter. The air guide assists inbreaking up this jet stream so the air exits the air exhaust moreevenly. The reduction or prevention of the jet stream air flow tendencyreduces the amount of settled particles which are stirred up as the airexits the air exhaust. The air guide also can function to limit theaccess between the vanes. The air guide can also reduce vibrationaland/or whistling noises caused by a jet stream thereby making the aircleaner quieter during operation. In one aspect of this embodiment, theair guides are substantially symmetrically oriented to one another. Inanother aspect of this embodiment, the air guides are not symmetricallyoriented to one another. The non-symmetrical orientation of the airguides can reduce the amount of vibrational noise during the operationof the air cleaner.

In accordance with yet a further aspect of the present invention, themotor mechanism of the air cleaner is located within the housing to drawair through the air intake, through one or more filters, into the innerchamber of the housing and to expel the filtered air out through the airexhaust. In one embodiment, the motor mechanism includes an electricmotor which drives a blade that creates a vacuum in the inner chamber ofthe housing which results in air being drawn into the air intake andthrough the one or more air filters. In another embodiment, a particlefilter is disposed between the air intake and inner chamber of the aircleaner to remove a wide variety of particles entrained in the air. Inone aspect of this embodiment, the particle filter is a filter whichremoves at least about 99.97% of the particles entrained in the airhaving a size greater than about 0.3 micron. In another aspect of thisembodiment, the particle filter is a filter which removes at least about99.98% of the particles entrained in the air having a size greater thanabout 0.1 micron. In yet another aspect of this embodiment, the particlefilter can be made of one or more filter layers. In one arrangement ofthis aspect of this embodiment, the particle filter is a single filtermade of multiple filter layers. In another arrangement of this aspect ofthis embodiment, the particle filter is a plurality of single layerfilters. In yet another arrangement of this aspect of this embodiment,the particle filter is a plurality of filters, which filters are singlelayer filters and/or multiple layer filters. In still another aspect ofthis embodiment, the filter removes particles from the air mechanicallyand/or by electrical attraction. The composition of the filter typicallyincludes the composition of the filters disclosed in Assignee's U.S.Pat. Nos. 5,248,323; 5,593,479; 5,641,343; 5,651,811; 5,837,020 andAssignee's U.S. patent application Ser. No. 09/032,589 filed Feb. 27,1998, which are incorporated herein by reference.

In accordance with still a further aspect of the present invention, agas filter is used in combination with the particle filter in the aircleaner to remove gases such as smoke, fumes, gas contaminants, and/ornoxious gases from the filtered air. In one embodiment, the gas filteris positioned adjacent to the particle filter. In another embodiment,the gas filter is connected to and/or forms a part of the particlefilter. In still another embodiment, the gas filter includes activatedcharcoal to absorb one or more gases from the filtered air. In oneaspect of this embodiment, the gas filter is formed of non-wovenactivated charcoal matting. One type of non-woven material that can beused is a non-woven polyester material impregnated with activatedcarbon. In another aspect of this embodiment, the mat has a thickness ofup to about 1.0 inch. In still another aspect of this embodiment, themat has a sponge texture to increase the surface area of the activatedcarbon.

In accordance with still yet a further aspect of the present invention,one or more filters in the air cleaner are cylindrical in shape toincrease the surface area to provide increased filtering efficiencies.In one embodiment, the particle filter is cylindrical in shape. Inanother embodiment, the gas filter is cylindrical in shape. In stillanother embodiment, the particle filter and the gas filter arepositioned adjacent to one another thereby minimizing the area taken upby the filters and to ensure that the filters are properly positioned inthe air cleaning system.

In accordance with another aspect of the present invention, a supportmechanism is employed to maintain the particle filter and/or the gasfilter in a proper position and to support the particle filter and/orgas filter during the filtration of the air. The support mechanism canbe incorporated into the filters themselves and/or can be an externalmechanism such as a frame to hold the particle filter and/or gas filterin place. The support mechanism is designed to support and maintain theparticle filter and/or gas filter in position without impairing the airflow through the particle filter and/or gas filter.

In accordance with still another aspect of the present invention, theair filters in the air cleaner do not cause a large pressure drop as theair passes through the filter system. The fibers in the particle filterare designed to mechanically trap and/or electrically attract particlesentrained in the air as they pass through the filter so as not to impairthe air flow through the air filters. Furthermore, the other componentsof the air cleaner are designed to minimize pressure drop through theair cleaner. As a result, the air cleaner can use a smaller motor sothat the air cleaner can have a more compact and portable design.

The primary object of the present invention is the provision of an aircleaner which can efficiently and effectively filter out particlesentrained in the air.

Another object of the present invention is the provision of an aircleaner designed to have a large volume of air intake and a large volumeof air exhaust with relatively low air velocity into and out of the aircleaner.

Yet another object of the present invention is the provision that thefilter element in the air cleaner can be easily changed when the filterbecomes clogged or partially clogged, or old.

Still a further object of the present invention is an air cleaner whichincludes using a particle filter in combination with a gas filter toremove both particles and unwanted gases from the air.

In accordance with another object of the present invention, the particlefilter and the gas filter are disposed in a coterminous relationship toone another and supported by a support structure.

In accordance with another object of the present invention, the aircleaner is designed to minimize the air pressure drop throughout the aircleaner thereby reducing the need for a large motor to draw in and expelair from the air cleaner.

In accordance with yet another object of the present invention, thedischarge of air is expelled by outwardly radiating vanes which reducepressure drop and noise during operation.

In accordance with another object of the present invention, the vanesare specially designed to reduce noise during and have improved airwithdrawal efficiencies.

In accordance with still another object of the present invention, one ormore of the vanes are not symmetrically oriented with respect to oneanother.

In accordance with another object of the present invention, one or moreof the vanes are not harmonically oriented and/or shaped with respect toone or more of the other vanes.

In accordance with yet another object of the present invention, one ormore of the vanes are not made of the same material with respect to oneor more of the other vanes.

In accordance with still another object of the present invention, theair exhaust includes air guides to disperse filtered air from the airexhaust.

It is another object of the present invention to provide an air cleaner,wherein the discharge of air is generally radially outward from theentire periphery of the air cleaner housing so as to uniformlydistribute the filtered air.

It is another object of the present invention to provide an air cleanerwherein air is drawn radially inwardly from the entire periphery of theunit near the base of the unit and the air is discharged outwardly aboutthe entire periphery of the unit above the air intake.

In accordance with yet another object of the present invention, the aircleaner discharges filtered air without disturbing and/or causingsettled particles to be recirculated in an environment.

It is still another object of the present invention to design a compactand portable air cleaner which can be easily moved to different rooms bya user.

These and other objects and advantages will become apparent to thoseskilled in the art upon reading the following description taken togetherwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the drawings, which illustrate variousembodiments that the invention may take in physical form and in certainparts and arrangement of parts herein:

FIG. 1 is a cross-sectional view of the assembled air cleaner of thepresent invention;

FIG. 2 is a cross-sectional view taken along line 2—2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along line 3—3 of FIG. 2;

FIG. 4 is a cross-sectional view taken along line 4—4 of FIG. 2;

FIG. 4A is a cross-sectional view of an alternative vane arrangementtaken along line 4—4 of FIG. 2;

FIG. 4B is a cross-sectional view of another alternative vanearrangement taken along line 4—4 of FIG. 2;

FIG. 5 is a modified view of FIG. 2 illustrating a single vane radiatingoutwardly from the center of the air cleaner of the present invention;

FIG. 6 is a top view of a plurality of vanes positioned about the centerof the air cleaner of the present invention;

FIG. 7 is a sectional view of the leading end of a vane;

FIG. 8 is a sectional view of an alternative design of the leading endof a vane;

FIG. 9 is a sectional view of another alternative design of the leadingend of the vanes in the air cleaner;

FIG. 10 is a cross-sectional view taken along line 10—10 of FIG. 2;

FIG. 10A is an alternative cross-sectional view taken along line 10—10of FIG. 2;

FIG. 11 is a perspective view of a single vane; and

FIG. 12 is a modified view of FIG. 2 illustrating the use of air guides.

PREFERRED EMBODIMENTS OF THE INVENTION

Referring now to the drawings wherein the showings are for the purposeof illustrating the preferred embodiment of the invention only and notfor the purpose of limiting the same, FIG. 1 illustrates a portable aircleaner 10. Air cleaner 10 includes a housing made up of an upperhousing 20A and a lower housing 20B. Both the upper and lower housingsare generally cylindrical. Lower housing peripheral surface 22B includesair intake 24. Air intake 24 is positioned about the complete peripheralsurface of lower housing 20B and includes multiple holes or slots inperipheral surface 22B. The size of the slots or holes in air intake 24are typically sized such that a user cannot insert his or her fingersinto the slots or holes and damage the interior of air cleaner 10.

Air intake 24 is positioned on the lower part of air cleaner 10 so as todraw in unfiltered air at or near the base of air cleaner 10. Aircleaner 10 reduces and/or prevents the recirculation of settledparticles by intaking unfiltered air at or near the base of air cleaner10 and expelling the filtered air at or near the top of air cleaner 10.Many of the particles which are disturbed by the air flow into the aircleaner will be drawn into the air cleaner 10 and filtered by the aircleaner 10. The positioning of the air intake 24 about the completeperipheral surface of the lower housing 20B results in a larger surfacearea for unfiltered air to flow into the air cleaner 10, therebyresulting in a high volume of air drawn into the air cleaner 10 withoutcreating high velocities of air into the air cleaner 10. The velocityreduction of the air into the air cleaner 10 reduces and/or preventsproblems associated with disturbing settled particles about the aircleaner 10.

Mounted onto lower housing base 30 is a bumper 34. Bumper 34 isconnected to the lower housing 20B by bumper leg 32 which is positionedoutside of the peripheral surface 22B adjacent to base surface 44 asillustrated in FIG. 1. Bumper 34 is typically made of a plastic and/orrubber material which is designed to absorb vibration and noise, therebyproviding for a quiet operation of air cleaner 10.

As shown in FIG. 1, upper housing 20A includes an upper housingperipheral surface 22A which incorporates air exhaust 26. Air exhaust 26is positioned completely about the peripheral surface 22A. The airexhaust 26 includes a plurality of vanes 170 which function and designwill be described in more detail below. The positioning of the airexhaust about the complete peripheral surface 22A of the upper housing20A increases the surface area of the openings of the air exhaust 26thereby allowing a large volume of air to be expelled from air cleaner10 without creating high air velocities. As discussed above, highvelocity air can cause settled particles to be inadvertentlyrecirculated into a room. The positioning of air exhaust 26 on upperhousing 20A distances the air exhaust 26 from the base of air cleaner 10thereby significantly reducing the occurrences of filtered air exitingair cleaner 10 and disturbing particles which have settled on a floorsurface near air cleaner 10.

Lower housing 20B includes an inner chamber 40. Inner chamber 40 isgenerally cylindrical in shape and has a generally uniformcross-sectional diameter along the longitudinal axis of the innerchamber. Inner chamber 40 includes a side wall 42 which defines theinterior surface of air intake 24. The interior chamber also includes abase surface 44.

A filter ledge 46 is positioned on base surface 44 and is spaced fromside wall 42. The filter ledge extends about base surface 44 of innerchamber 40. Filter ledge 46 is shown mounted to be generallyperpendicular to base surface 44 and generally parallel to side wall 42.

Extending from the top of filter ledge 46 is air deflector 50. Airdeflector 50 extends at some non-perpendicular angle from filter ledge46 toward the interior of inner chamber 40. The air deflect also extendscompletely about the central axis of the inner chamber. The slopesurface of air deflector 50 causes the air entering inner chamber 40 tobe directed upwardly and toward air exhaust 26. Air deflector 50 extendsinto the interior of inner chamber 40 until it contacts motor supportguide surface 52. Guide surface 52 extends toward the central axis ofinner chamber 40 at a downward angle. Guide surface 52 extends uniformlyabout the central axis of inner chamber 40 thereby forming a conicalsurface near the central axis of inner chamber 40. Guide surface 52 isdesigned to guide threaded surface 62 of motor support 60 toward supporthole 54 located at the central axis of inner chamber 40. As illustratedin FIG. 1, filter base surface 44, air deflector surface 50 and guidesurface 52 define the complete base of lower housing 20B.

As best shown in FIG. 1, particle filter 80 is positioned between sidewall 42 and filter ledge 46. Particle filter 80 is shown to be generallycylindrical and having a thickness which is less than or equal to thedistance between side wall 42 and filter ledge 46. Filter ledge 46maintains particle filter 80 in position so that the particle filterdoes not move as unfiltered air enters intake 24 and passes throughparticle filter 80. Particle filter 80 is positioned on top of filtersupport 88. The filter support 88 and the filter ledge 46 maintain thebottom edge of particle filter 80 in proper position with respect to thebase of lower housing 20. Filter support 88 provides a small spacebetween filter outer layer 82 and side wall 42. This small space ensuresthat particle filter 80 is not damaged during the operation of the aircleaner 10. Filter support 88 also acts as an air seal to prevent airfrom flowing under the particle filter 80 and into the interior of innerchamber 40 without being filtered.

At the top of particle filter 80 is a filter seal 90. This filter seal90 works in conjunction with filter support 88 to maintain particlefilter 80 in its proper position within inner chamber 40 throughout thelongitudinal axis of the inner chamber. Filter seal 90 creates a smallspace between filter outer layer 82 and side wall 42. Filter seal 90also prevents air from traveling about the top of particle filter 80 andinto the interior inner chamber 40 without prior to being filtered.

Particle filter 80 is typically a HEPA filter which is designed toremove at least about 99.97% of particles entrained in the air which areabout 0.3 micron in size. Preferably particle filter 80 removes at leastabout 99.98% of particles about 0.1 micron in size. The particle filteris typically suitable for use in high temperatures and high stressenvironments. Filter types which can be used are disclosed in Assignee'sU.S. Pat. Nos. 5,248,323; 5,593,479; 5,641,343; 5,651,811; 5,837,020 andAssignee's U.S. patent application Ser. No. 09/032,589 filed Feb. 27,1998.

As shown in FIG. 1, air cleaner 10 includes a gas filter 160 positionedcoterminous to inner layer 86 of particle filter 80. Carbon filter 160is typically cylindrical and is formed of a layer of non-woven activatedcharcoal matting. The activated charcoal is impregnated into thenon-woven mat. The mat has a thickness of less than about 1 inch and istypically about 0.125-0.5 inch in thickness. The gas filter is designedto remove irritating and/or noxious gases which freely pass throughparticle filter 80. As can be appreciated, the gas filter can be made apart of the particle filter. Types of gas filters that can be used aredisclosed in Assignee's U.S. Pat. Nos. 5,248,323; 5,593,479; 5,641,343;5,651,811; 5,837,020 and Assignee's U.S. patent application Ser. No.09/032,589 filed Feb. 27, 1998.

Referring again to FIG. 1, upper housing 20A includes a motor chamber110. Motor chamber 110 includes a chamber top 111 which defines the topof the chamber. Within motor chamber 110 is positioned centrifugal fan114. Centrifugal fan 114 has a plurality of fan blades 115. Thecentrifugal fan 114 includes a fan mount 117 which connects to motorshaft 116 of motor 112. Centrifugal fan 114 is designed to be rotated bymotor 112 and to draw air into inner chamber 40 through air intake 24and expel air through air exhaust 26. As the air is drawn from innerchamber 40, a vacuum is created within inner chamber 40 which causes theair outside of air cleaner 10 to be drawn through air intake 24 andthrough particle filter 80 and carbon filter 160. Motor 112 is typicallyan electric motor which is energized by electricity traveling throughmotor cord 74 and into motor 112 via motor power cord inlet 118. Motorcord 74 is connected to an external power source by motor cord connector76 connecting to power cord connector 72 in cord connector hole 56 ofair deflector surface 50 located at the housing base 30. Power cordconnector 72 is secured in connection hole 56 by connector clip 58. Thepower cord 70 extends from power cord connector 72 to an electricaloutlet thereby providing energy or electricity to motor 112.

The speed at which motor 112 is operated is controlled by switch 152located in switch chamber 150. Switch chamber 150 is formed by topsection 106. Top section 106 is shown to be mounted onto air exhaust topedge 100 at top section mounting surface 108. Switch 152 is mounted toswitch chamber 150 by a nut arrangement or by some other mountingarrangement. Switch 152 includes a switch knob 153 which can be rotatedby the user to vary the power to motor 112 via switch cord 159 toincrease and/or decrease the motor speed. The motor typically includesan over heating reset circuit to temporarily shut off the motor when itoverheats. Such overheating typically is caused by the insufficient flowof air through the air cleaner.

As illustrated in FIG. 1, motor 112 and centrifugal fan 114 aremaintained in motor chamber 110 by motor guard 130. Motor 112 rests uponguard base 132 and is further supported by motor support 60 whichextends from motor guard base 132 to housing base 30. Motor guard 130includes a mount hole 138 which mounts motor support 60 to motor guard130 by support mount 66. Motor support 60 extends through housing base30 via support hole 54 in guide surface 52. Motor support 60 is securedat the housing base 30 by screwing on support knob 64 onto threadsurface 62 of motor support 60. Motor 112 is energized by motor cord 74which passes through cord access 148 of motor guard 130. Motor cord 74is maintained in position in motor guard 130 by access plug 149.

Motor guard 130 is mounted to upper housing 20A by inserting guardconnector 146 through mount hole 138. The guard connectors are typicallyscrews and/or bolts. Motor guard 130 is connected to the base of motor112 by nut and bolt arrangement 120. Motor guard 130 includes an airseal surface 140 which contacts filter seal 90 to form an air sealbetween upper housing 20A and lower housing 20B. Motor guard 130 alsoincludes an upper housing seal surface 142 which seals bottom edge 102of upper housing peripheral surface 22A with motor guard 130. Motorguard 130 further includes a lower housing seal surface 144 which isdesigned to be slidably engageable about lower housing peripheralsurface 22B and air intake top edge 104. Sealing surfaces 142 and 144 onmotor guard 130 effectively seal the upper housing 20A and lower housing20B together when air cleaner 10 is fully assembled.

Motor guard 130 is designed to mount motor 112 into upper housing 20A asdescribed above and to provide a sufficient air flow access from innerchamber 40 to motor chamber 110 so as to minimize the pressure dropbetween the two chambers. As illustrated in FIG. 1, a space existsbetween motor 112 and filters 80 and 160. The space allows the filteredair to flow between inner chamber 40 and motor chamber 110. Motor guard130 is mounted between the space to prevent a user from freely accessingthe motor and fan in the motor chamber. Air slots 134 are positionedthroughout motor guard 130 to preferably provide a slot space surfacearea which is at least equal to the cross-sectional surface area of thespace between motor 112 and filters 80 and 160. To increase the slotspace surface area, motor guard 130 extends from the base of upperhousing 20A into inner chamber 40 when the air cleaner 10 is fullyassembled as shown in FIG. 1.

Referring now to FIGS. 2-12, there is illustrated, in detail, vanes 170in air exhaust 26. As shown in FIGS. 2, 4, 4A, 4B and 12, air exhaust 26includes a plurality of vanes 170 disposed about the perimeter of blade115 of centrifugal fan 114. FIG. 2 illustrates four vanes 170 spacedabout centrifugal fan 114. As can be appreciated, more or less vanes maybe incorporated into the air exhaust depending on the diameter of theair exhaust. FIG. 2 illustrates a centrifugal fan 114 having a diameterof about 9-13 inches surrounded by four vanes 170 which radiateoutwardly to form an air exhaust having a diameter of about 10-14inches. Each vane is illustrated to be about 10-18 inches in length. Ascan be appreciated, the diameter of fan 114, and the dimensions of vanes170 can be varied, depending on dimensional requirements. Each vane 170includes a front end 180 and a back end 186. The front end of the vanesis positioned closest to blade 115 of centrifugal fan 114.

As best illustrated in FIGS. 5 and 6, the vanes have a varying radius ofcurvature from the front to back end. The radius of curvature at thefront end of the vane is less than the radius of curvature at the backend of the vane. In addition, the center of curvature is positioneddifferently with respect to different sections of the vane. As a result,the vanes are substantially like volute shaped members positioned aboutthe centrifugal fan 114. FIGS. 5 and 6 also illustrate the relativedistances the vanes are positioned from one another and positioned fromthe centrifugal fan. Referring specifically to FIG. 5, distance arepresents the distance vane front end 180 is positioned fromcentrifugal fan 114 and distance d represents the distance vane back end186 is positioned from centrifugal fan 114. Distance a is less thandistance d. Typically, distance a is less than about one inch andtypically about 0.05 to 0.4 inch, and preferably about 0.125 to 0.25inch from blade 115. A distance a of less than about 0.5 inch is typicalfor blade diameters of less than about 36 inches. Distance d isprimarily dependent on the desired outer diameter of air exhaust 26.Typically, distance d ranges from about 1.0-2.5 inches for a bladehaving a diameter of about 5-20 inches. Distances b and c represent theradius of curvature of the vane. Distance b is shown to be less thandistance c and each radius has a different center of curvature. For avane of about 10-18 inches in length, distance b is about 3.58 inchesand distance c is about 4.75-12 inches. As can be appreciated, differentvane curvatures and lengths can be used to accommodate different aircleaner designs. However, the vane front end should be positionedclosely to the centrifugal fan 114 to remove as much air from the bladeof the centrifugal fan 114 as possible.

Referring now to FIG. 6, the relative space relationship of the vaneswith respect to one another is illustrated. Distance e is the distanceof vane front end 180 from an adjacently positioned vane and distance fis the distance of vane back end 186 from an adjacently positioned vane.The vanes are positioned about the centrifugal fan 114 such thatdistance f is greater than distance c. For vanes of about 10-18 inches,distance e is typically about 0.35-1.5 inches and distance f istypically about 0.5-2 inches; however, other distance relationships canbe used. Distances e and f can be the same or different for two of moreof the vanes positioned in the air exhaust.

Referring now to FIGS. 2 and 4, vanes 170 are mounted onto vane mountsurface 143 of the upper housing. Each vane 170 includes a plurality ofmount holes 172 designed to receive a vane connector 174 to secure thevanes 170 to the upper housing and about centrifugal fan 114. At leastone of vanes 170 includes a cord opening 184 to provide access forswitch cord 159 as shown in FIG. 1. As illustrated in FIGS. 2 and 4,front end 180 of each vane 170 is spaced at substantially the samedistance from blade 115. FIGS. 2 and 4 also illustrate that the frontend of each vane 170 are not symmetrically oriented about blade 115 andthat the front ends of the vanes 170 are not spaced at equal distancesfrom the front ends of adjacently positioned vanes. As specificallyshown in FIG. 4, the length of front end 180 of each vane is a differentlength. The length of the front end of the first vane is 30°. The lengthof the front end of the second vane is 38°. The length of the front endof the third vane is 41°. The length of the front end of the fourth vaneis 44°. As a result of these front end vane lengths, the distancebetween the front ends of the forth vane and the first vane is about81.75°; the distance between the front ends of the first vane and thesecond vane is about 89.75°; the distance between the front ends of thesecond vane and the third vane is about 92.75°; and the distance betweenthe front ends of the third vane and the fourth vane is about 95.75°.Furthermore, FIGS. 2 and 4 illustrate that back end 186 of each vane issymmetrically oriented about the peripheral edge of the air exhaust andthat the back ends of the vanes are spaced at substantially equaldistances from the back ends of adjacently positioned vanes. In thisvane configuration, the length of all the vanes is different. FIGS. 2and 4 also illustrate that the radius of curvature of each vane frommount holes 172 to the back ends are substantially the same for eachvane, and that the radius of curvature of each vane is different fromthe front end to mount holes 172. The unsymmetrical design of the vanesin the air exhaust counters any harmonic vibration of the vanes duringthe operation of the air cleaner.

A linear form of the four vanes of FIGS. 2 and 4 prior to being mountedin the air exhaust is illustrated in FIG. 9. The length of each vane isdifferent. In addition, the angle of the sloped surface of the front endof each vane is also different. Furthermore, the length and profile oftapered edge 182 of each vane is also different. As best shown in FIG.6, vane front end 180 includes a tapered edge 182. Tapered edge 182 isdesigned further to reduce whistling noise and vibration noise as thefiltered air is drawn off of centrifugal fan 114 by vanes 170.Typically, the tapered edge 182 is a smooth, curved surface. FIG. 11illustrates the profile of one of the curved vanes of FIGS. 2 and 4.

Referring now to FIG. 4A, a modification to the vane design isillustrated. In FIG. 4A, vanes 170 are mounted onto vane mount surface143 of the upper housing 20A in a similar fashion as shown in FIGS. 2and 4. Also similar to FIGS. 2 and 4, front end 180 of each vane 170 asshown in FIG. 4A is spaced at substantially the same distance from blade115. FIG. 4A, like FIGS. 2 and 4, shows the front end of each vane notsymmetrically oriented about blade 115 and that the front ends of thevanes are not spaced at equal distances from the front ends ofadjacently positioned vanes. Indeed, the spacing of the front end 180 ofeach vane from adjacent vanes is similar to the spacing illustrated inFIG. 4. However, the vanes in FIG. 4A are dissimilar to the vanes inFIGS. 2 and 4 in that the length of the vanes are substantially thesame. As a result, the back end 186 of each vane 170 is notsymmetrically oriented about the peripheral edge of the air exhaust 10and that the back ends 186 of the vanes 170 are spaced at differentdistances from the back ends of adjacently positioned vanes. FIG. 4Aalso illustrates that the radius of curvature of each vane from mountholes 172 to the back ends 186 are different for each vane, and that theradius of curvature of each vane is different from the front end tomount holes 172. Similar to the vane design of FIGS. 2 and 4, theunsymmetrical design of the vanes in the air exhaust illustrated in FIG.4A counters any harmonic vibration of the vanes during the operation ofthe air cleaner.

Referring now to FIG. 4B, another modification to the vane design isillustrated. In FIG. 4B, vanes 170 are mounted onto vane mount surface143 of the upper housing 20A in a similar fashion as shown in FIGS. 2and 4. FIG. 4B, like FIGS. 2 and 4, shows the front end of each vane notsymmetrically oriented about blade 115 and that the front ends of thevanes are not spaced at equal distances from the front ends ofadjacently positioned vanes. Indeed, the spacing of the front end 180 ofeach vane from adjacent vanes is similar to the spacing illustrated inFIG. 4. Also similar to FIGS. 2 and 4, the vanes in FIG. 4B aredissimilar in length, the back end 186 of each vane is symmetricallyoriented about the peripheral edge of the air exhaust 10 and the backends of the vanes are spaced at substantially the same distances fromthe back ends of adjacently positioned vanes. FIG. 4B also illustratesthat the radius of curvature of each vane from mount holes 172 to theback ends are the same for each vane, and that the radius of curvatureof each vane is different from the front end to mount holes 172.However, the vane design illustrated in FIG. 4B is different from thevane design shown in FIGS. 2 and 4 in that front end 180 of each vane asshown in FIG. 4B is spaced at different distances from blade 115.Similar to the vane design of FIGS. 2 and 4, the unsymmetrical design ofthe vanes in the air exhaust illustrated in FIG. 4A counters anyharmonic vibration of the vanes during the operation of the air cleaner.

Referring now to FIGS. 3, 7, 8 and 9, vane front end 180 is a slopedsurface which slopes downwardly from the top to the bottom of the vane.FIG. 7 illustrates the sloped surface as being a linear slope and FIG. 8illustrates the sloped surface as being non-linear. The sloped surfacefunctions to reduce noise during operation by eliminating a straightedged surface which typically causes a whistling noise as air passes theedge. The sloping of the vane front end reduces this noise generation.This allows the vane to be positioned closely to the centrifugal fan todraw off additional quantities of air without additional noisegeneration. The sloped surface also reduces the amount of vibration ofthe vane front end, thus further reducing noise generation andincreasing air removal efficiencies. A slope angle of about 10-50degrees, preferably about 20-40 degrees, and more preferably about 25-35degrees results in the desired reduction in noise generation. If theslope is non-linear as shown in FIG. 8, the linear slope formed from thetop and bottom ends of the vane, as represented by the dashed line,preferably has an angle of 10-50 degrees. One example of a vane whichincludes these enhanced features is a vane wherein distance m is about13-14 inches, distance n is 15.25-16 inches, distance o is 3.5-4.25inches and angle x is 20-40 degrees.

Referring now to FIG. 10, the vane front end 180 of one of the vanes ofFIGS. 2 and 4 is illustrated. The vane front end is spaced closelyadjacent to blade 115 of centrifugal fan 114. Tapered end 182 tapersslightly away from blade 115. A modification to the vane front end isillustrated in FIG. 10A. The thickness of vane front end 180 is shown tobe less than the thickness of vane front end 180 of FIG. 10. Theharmonics of the vanes in the air exhaust can be countered by usingvanes with different vane front end thicknesses as shown in FIGS. 10 and10A.

Another modification of air exhaust 26 is illustrated in FIG. 12. An airguide 190 is positioned between two vanes 170. The air guide 190 istypically positioned at a substantially equal distance from adjacentlypositioned vanes and typically positioned near vane back end 186.However, the air guides can be non-uniformly positioned between thevanes and positioned at differing locations relative to the vane backends. The air guide typically has a height substantially equal to theadjacently positioned vanes but its length is substantially shorter thanvanes 170. For vanes of about 10-18 inches, the air guide is typicallyabout 1-4 inches; however, other lengths may be used. The air guide 190can include tapered ends and/or be curved along its longitudinal length.The air guide 190 is designed to assist in directing the flow of airbeing expelled from air exhaust 26. As the expelled air travels alongthe inner surface of each vane, the air may tend to follow a singlenarrow path, thus resulting in relatively higher velocities when leavingthe air exhaust. The air guide is designed to break up this narrow airpath and force the air to flow out in a less narrow path from the vanes.This wider path of air flow reduces air velocities from the vaneswithout impairing air flow which could cause increased pressure drop.For relatively wide spaced vanes, multiple air guides may be used toredirect air flow. The air guides also serve as a secondary function tolimit access to the interior of the air exhaust.

The specially designed air exhaust significantly reduces the pressuredrop between the centrifugal fan and the exterior of the air exhaust.This significant pressure drop reduction allows for small motors to beused or smaller air exhaust surface areas for similar sized motors to beused. The vane design also provides for quieter operation. The slopedsurfaces and/or tapered edges reduces vibration frequencies which cancause added noise during operation. The unsymmetrical design and/ororientation of the vanes reduces the harmonics of the vanes duringoperation, thus reducing vibration and vibrational noise of the vanesduring operation. The unique vane design used in the air exhaust canalso remove the same volume of air at 20-25% fan speed as compared tostandard mesh design air exhausts running at 100% fan speed.

Referring now to FIG. 1, a handle 154 is mounted onto top section 106 sothat a user can conveniently move air cleaner 10 to various locationswithin a room or building. Handle 154 is mounted to top section 106 byhandle mount 156 which allows handle 154 to pivot on top section 106. Ahandle slot 158 is provided in top section 106 such that the handle maybe pivoted downwardly into the slot to maintain the handle in a secureposition.

The steps of changing particle filter 80 and/or gas filter 160 will nowbe described. Air cleaner 10 is designed such that the filters withinthe air cleaner 10 can be conveniently and easily removed and replacedto ensure that the air filters are properly removing particles and gasesentrained in the air at the desired efficiency. As discussed above, anoperator activates air cleaner 10 by rotating switch knob 153 on switch152 the “on” position thereby energizing motor 112 which in turn causescentrifugal fan 114 to rotate. The speed of rotation of centrifugal fan114 may be adjusted by switch 152. Air cleaner 10 is turned off when theoperator turns the rotating switch knob 153 to the “off” position. Thefilters within air cleaner 10 can be easily removed by the operator bysimply tilting the air cleaner 10 on its side and removing support knob64 from threaded surface 62 of motor support 60. Once support knob 64has been removed from motor support 60, air cleaner 10 is tilted backupon its base. Upper housing 20A is then separated from lower housing20B by the operator grasping handle 154 and raising upper housing 20Afrom lower housing 20B. Raising upper housing 20A causes threadedsurface 62 of motor support 60 to retract through support hole 54. Theupper housing 20A is completely removed from the lower housing 20B bythe operator reaching into inner chamber 40 and disengaging motor cordconnector 76 from power card connector 72.

Once upper housing 20A is removed from lower housing 20B, particlefilter 80 and gas filter 160 are easily removed from inner chamber 40 bylifting the two filters out of the inner chamber 40. A new particlefilter 80 can then be reinserted into inner chamber 40 and set into basesurface 44 at housing base 30. Gas filter 160 can then be insertedwithin particle filter 80 and coterminous to filter inner layer 86 asillustrated in FIG. 1. Once the filters have been properly inserted intoinner chamber 40, upper housing 20A is replaced on lower housing 22B. Asupper housing 20A is partially lowered onto lower housing 20B, theoperator is able to reconnect motor cord connector 76 with powerconnector 72. The upper housing 20A is then fully lowered onto lowerhousing 20B . Threaded surface 62 of motor support 60 is easily guidedinto support hole 54 by guide surface 52. Once threaded surface 62 hasbeen inserted through support hole 54 and the lower housing sealingsurface 144 of motor guard 130 are engaged about the peripheral surface22B near air intake top edge 104, support knob 64 is again rethreadedonto threaded surface 62 of motor support 60. The threading of supportknob 64 secures the upper housing and lower housing together.

The invention has been described with reference to a preferredembodiment and alternates thereof. It is believed that manymodifications and alterations of the embodiments disclosed will readilysuggest themselves to those skilled in the art upon reading andunderstanding the detailed description of the invention. It is intendedto include all such modifications and alterations insofar as they comewithin the scope of the present invention.

Having thus defined the invention, the following is claimed:
 1. Aportable air cleaner that generates less vibrational noise duringoperation comprising a housing having an outer peripheral edge and aninner chamber, an air intake, air exhaust that provides a passageway forthe expulsion of air from said inner chamber, a blower having a blade todraw air into said inner chamber through said air intake and to expelair from said inner chamber through said air exhaust, a filter disposedbetween said air intake and air exhaust to at least partially filter airdrawn through said air intake, the improvement comprising said airexhaust having a plurality of arcuate vanes radiating outwardly fromsaid blower, at least a portion of two of said arcuate vanes positionednon-symmetrically relative to said blade, said at least two of saidarcuate vanes directing said air from said blade in a substantiallyunobstructed manner to said outer peripheral edge of said housing. 2.The air cleaner as defined in claim 1, wherein each of said arcuatevanes having a length, at least one of said arcuate vanes having alength that is different from the length of at least one other arcuatevane.
 3. The air cleaner as defined in claim 2, wherein each of saidarcuate vanes has a different length.
 4. The air cleaner as defined inclaim 1, wherein each of said arcuate vanes has a radius of curvatureover at least a portion of the length of said arcuate vane, at least oneof said arcuate vanes having a radius of curvature that is differentfrom the radius of curvature of at least one other arcuate vane.
 5. Theair cleaner as defined in claim 2, wherein each of said arcuate vaneshas a radius of curvature over at least a portion of the length of saidarcuate vane, at least one of said arcuate vanes having a radius ofcurvature that is different from the radius of curvature of at least oneother arcuate vane.
 6. The air cleaner as defined in claim 3, whereineach of said arcuate vanes has a radius of curvature over at least aportion of the length of said arcuate vane, at least one of said arcuatevanes having a radius of curvature that is different from the radius ofcurvature of at least one other arcuate vane.
 7. The air cleaner asdefined in claim 4, wherein each of said arcuate vanes has a differentradius of curvature.
 8. The air cleaner as defined in claim 6, whereineach of said arcuate vanes has a different radius of curvature.
 9. Theair cleaner as defined in claim 1, wherein at least two of said arcuatevanes having two ends, said first end positioned closely adjacent tosaid blade and said second end positioned at least closely adjacent tosaid outer peripheral edge of said housing, at least one of said arcuatevanes having a first end spaced closer to said blade than the first endof at least one other arcuate.
 10. The air cleaner as defined in claim2, wherein at least two of said arcuate vanes having two ends, saidfirst end positioned closely adjacent to said blade and said second endpositioned at least closely adjacent to said outer peripheral edge ofsaid housing, at least one of said arcuate vanes having a first endspaced closer to said blade than the first end of at least one otherarcuate.
 11. The air cleaner as defined in claim 4, wherein at least twoof said arcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, at least one ofsaid arcuate vanes having a first end spaced closer to said blade thanthe first end of at least one other arcuate.
 12. The air cleaner asdefined in claim 8, wherein at least-two of said arcuate vanes havingtwo ends, said first end positioned closely adjacent to said blade andsaid second end positioned at least closely adjacent to said outerperipheral edge of said housing, at least one of said arcuate vaneshaving a first end spaced closer to said blade than the first end of atleast one other arcuate.
 13. The air cleaner as defined in claim 9,wherein the first end of each of said arcuate vanes is spaced from saidblade a different distance.
 14. The air cleaner as defined in claim 12,wherein the first end of each of said arcuate vanes is spaced from saidblade a different distance.
 15. The air cleaner as defined in claim 1,wherein at least two of said arcuate vanes having two ends, said firstend positioned closely adjacent to said blade and said second endpositioned at least closely adjacent to said outer peripheral edge ofsaid housing, said first end of at least one of said arcuate vanesspaced a greater perimeter distance about said blade from the first endof an adjacent arcuate vane than the perimeter distance about said bladefrom the first end of another adjacent arcuate vane.
 16. The air cleaneras defined in claim 2, wherein at least two of said arcuate vanes havingtwo ends, said first end positioned closely adjacent to said blade andsaid second end positioned at least closely adjacent to said outerperipheral edge of said housing, said first end of at least one of saidarcuate vanes spaced a greater perimeter distance about said blade fromthe first end of an adjacent arcuate vane than the perimeter distanceabout said blade from the first end of another adjacent arcuate vane.17. The air cleaner as defined in claim 4, wherein at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said first endof at least one of said arcuate vanes spaced a greater perimeterdistance about said blade from the first end of an adjacent arcuate vanethan the perimeter distance about said blade from the first end ofanother adjacent arcuate vane.
 18. The air cleaner as defined in claim9, wherein said first end of at least one of said arcuate vanes spaced agreater perimeter distance about said blade from the first end of anadjacent arcuate vane than the perimeter distance about said blade fromthe first end of another adjacent arcuate vane.
 19. The air cleaner asdefined in claim 14, wherein said first end of at least one of saidarcuate vanes spaced a greater perimeter distance about said blade fromthe first end of an adjacent arcuate vane than the perimeter distanceabout said blade from the first end of another adjacent arcuate vane.20. The air cleaner as defined in claim 18, wherein said first end ofeach arcuate vane being spaced a different perimeter distance about saidblade from the first end of an adjacent arcuate vane.
 21. The aircleaner as defined in claim 19, wherein said first end of each arcuatevane being spaced a different perimeter distance about said blade fromthe first end of an adjacent arcuate vane.
 22. The air cleaner asdefined in claim 1, wherein at least two of said arcuate vanes havingtwo ends, said first end positioned closely adjacent to said blade andsaid second end positioned at least closely adjacent to said outerperipheral edge of said housing, said first end of each vane has an endregion, said end region of at least one of said arcuate vanes has agreater thickness than the thickness of the end region of at least oneother arcuate vane.
 23. The air cleaner as defined in claim 2, whereinat least two of said arcuate vanes having two ends, said first endpositioned closely adjacent to said blade and said second end positionedat least closely adjacent to said outer peripheral edge of said housing,said first end of each vane has an end region, said end region of atleast one of said arcuate vanes has a greater thickness than thethickness of the end region of at least one other arcuate vane.
 24. Theair cleaner as defined in claim 4, wherein at least two of said arcuatevanes having two ends, said first end positioned closely adjacent tosaid blade and said second end positioned at least closely adjacent tosaid outer peripheral edge of said housing, said first end of each vanehas an end region, said end region of at least one of said arcuate vaneshas a greater thickness than the thickness of the end region of at leastone other arcuate vane.
 25. The air cleaner as defined in claim 9,wherein at least two of said arcuate vanes having two ends, said firstend positioned closely adjacent to said blade and said second endpositioned at least closely adjacent to said outer peripheral edge ofsaid housing, said first end of each vane has an end region, said endregion of at least one of said arcuate vanes has a greater thicknessthan the thickness of the end region of at least one other arcuate vane.26. The air cleaner as defined in claim 15, wherein said first end ofeach vane has an end region, said end region of at least one of saidarcuate vanes has a greater thickness than the thickness of the endregion of at least one other arcuate vane.
 27. The air cleaner asdefined in claim 21, wherein said first end of each vane has an endregion, said end region of at least one of said arcuate vanes has agreater thickness than the thickness of the end region of at least oneother arcuate vane.
 28. The air cleaner as defined in claim 22, whereinthe thickness of said end region of each of said arcuate vanes isdifferent.
 29. The air cleaner as defined in claim 27, wherein thethickness of said end region of each of said arcuate vanes is different.30. The air cleaner as defined in claim 1, wherein at least one of saidvanes overlaps at least a portion of an adjacently positioned vane. 31.The air cleaner as defined in claim 1, wherein said blade includes anaxis of rotation, at least two of said arcuate vanes having two ends,said first end positioned closely adjacent to said blade and said secondend positioned at least closely adjacent to said outer peripheral edgeof said housing, said first end of at least one of said arcuate vanesincluding a front face having a sloped surface along at least a portionof said first end, said sloped surface have an angle that is nonparallelto said axis of rotation of said blade.
 32. The air cleaner as definedin claim 1, wherein said blade includes an axis of rotation, at leasttwo of said arcuate vanes having two ends, said first end positionedclosely adjacent to said blade and said second end positioned at leastclosely adjacent to said outer peripheral edge of said housing, saidfront face of said first end of each of said arcuate vanes having anangle that is nonparallel to said axis of rotation of said blade, saidangle on said front face of said first end of at least one arcuate vanesbeing different from said angle on said front face of said first end ofat least one other arcuate vane.
 33. The air cleaner as defined in claim2, wherein said blade includes an axis of rotation, at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said front faceof said first end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 34. The air cleaner as defined in claim 4,wherein said blade includes an axis of rotation, at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said front faceof said first end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 35. The air cleaner as defined in claim 9,wherein said blade includes an axis of rotation, said front face of saidfirst end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 36. The air cleaner as defined in claim15, wherein said blade includes an axis of rotation, said front face ofsaid first end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 37. The air cleaner as defined in claim22, wherein said blade includes an axis of rotation, said front face ofsaid first end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 38. The air cleaner as defined in claim29, wherein said blade includes an axis of rotation, said front face ofsaid first end of each of said arcuate vanes having an angle that isnonparallel to said axis of rotation of said blade, said angle on saidfront face of said first end of at least one arcuate vanes beingdifferent from said angle on said front face of said first end of atleast one other arcuate vane.
 39. The air cleaner as defined in claim31, wherein said slope surface of at least one front face beingsubstantially linear.
 40. The air cleaner as defined in claim 39,wherein said slope surface of at least one front face being arcuate. 41.The air cleaner as defined in claim 1, wherein at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said second endof at least one of said arcuate vanes spaced a greater perimeterdistance about said outer peripheral edge from the second end on anadjacent arcuate vane than the perimeter distance about said outerperipheral edge from the second end of another adjacent arcuate vane.42. The air cleaner as defined in claim 2, wherein at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said second endof at least one of said arcuate vanes spaced a greater perimeterdistance about said outer peripheral edge from the second end on anadjacent arcuate vane than the perimeter distance about said outerperipheral edge from the second end of another adjacent arcuate vane.43. The air cleaner as defined in claim 4, least two of said arcuatevanes having two ends, said first end positioned closely adjacent tosaid blade and said second end positioned at least closely adjacent tosaid outer peripheral edge of said housing, wherein said second end ofat least one of said arcuate vanes spaced a greater perimeter distanceabout said outer peripheral edge from the second end on an adjacentarcuate vane than the perimeter distance about said outer peripheraledge from the second end of another adjacent arcuate vane.
 44. The aircleaner as defined in claim 9, wherein said second end of at least oneof said arcuate vanes spaced a greater perimeter distance about saidouter peripheral edge from the second end on an adjacent arcuate vanethan the perimeter distance about said outer peripheral edge from thesecond end of another adjacent arcuate vane.
 45. The air cleaner asdefined in claim 15, wherein said second end of at least one of saidarcuate vanes spaced a greater perimeter distance about said outerperipheral edge from the second end on an adjacent arcuate vane than theperimeter distance about said outer peripheral edge from the second endof another adjacent arcuate vane.
 46. The air cleaner as defined inclaim 22, wherein said second end of at least one of said arcuate vanesspaced a greater perimeter distance about said outer peripheral edgefrom the second end on an adjacent arcuate vane than the perimeterdistance about said outer peripheral edge from the second end of anotheradjacent arcuate vane.
 47. The air cleaner as defined in claim 32,wherein said second end of at least one of said arcuate vanes spaced agreater perimeter distance about said outer peripheral edge from thesecond end on an adjacent arcuate vane than the perimeter distance aboutsaid outer peripheral edge from the second end of another adjacentarcuate vane.
 48. The air cleaner as defined in claim 29, wherein saidsecond end of at least one of said arcuate vanes spaced a greaterperimeter distance about said outer peripheral edge from the second endon an adjacent arcuate vane than the perimeter distance about said outerperipheral edge from the second end of another adjacent arcuate vane.49. The air cleaner as defined in claim 41, wherein said second end ofeach arcuate vane being spaced a different perimeter distance about saidouter peripheral edge from the second end of an adjacent arcuate vane.50. The air cleaner as defined in claim 48, wherein said second end ofeach arcuate vane being spaced a different perimeter distance about saidouter peripheral edge from the second end of an adjacent arcuate vane.51. The air cleaner as defined in claim 1, wherein at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said housing, said first endof at least one of said vanes being tapered.
 52. The air cleaner asdefined in claim 1, wherein at least two of said arcuate vanes havingtwo ends, said first end positioned closely adjacent to said blade andsaid second end positioned at least closely adjacent to said outerperipheral edge of said housing, said first end of each vane beingtapered, at least one vane having a different tapered end from thetapered end of at least one other vane.
 53. The air cleaner as definedin claim 2, wherein at least two of said arcuate vanes having two ends,said first end positioned closely adjacent to said blade and said secondend positioned at least closely adjacent to said outer peripheral edgeof said housing, said first end of each vane being tapered, at least onevane having a different tapered end from the tapered end of at least oneother vane.
 54. The air cleaner as defined in claim 4, wherein at leasttwo of said arcuate vanes having two ends, said first end positionedclosely adjacent to said blade and said second end positioned at leastclosely adjacent to said outer peripheral edge of said housing, saidfirst end of each vane being tapered, at least one vane having adifferent tapered end from the tapered end of at least one other vane.55. The air cleaner as defined in claim 9, wherein said first end ofeach vane being tapered, at least one vane having a different taperedend from the tapered end of at least one other vane.
 56. The air cleaneras defined in claim 15, wherein said first end of each vane beingtapered, at least one vane having a different tapered end from thetapered end of at least one other vane.
 57. The air cleaner as definedin claim 32, wherein said first end of each vane being tapered, at leastone vane having a different tapered end from the tapered end of at leastone other vane.
 58. The air cleaner as defined in claim 41, wherein saidfirst end of each vane being tapered, at least one vane having adifferent tapered end from the tapered end of at least one other vane.59. The air cleaner as defined in claim 50, wherein said first end ofeach vane being tapered, at least one vane having a different taperedend from the tapered end of at least one other vane.
 60. The air cleaneras defined in claim 1, including at least one air flow distributorpositioned between at least two of said arcuate vanes.
 61. The aircleaner as defined in claim 1, wherein said air intake and said airexhaust positioned substantially about the periphery of said housing.62. The air cleaner as defined in claim 1, wherein said housing includesa lower section and an upper section, said air intake providing an airpassageway through said lower section and into said inner chamber, saidair exhaust providing an air passageway through said upper section forexpelling air from said inner chamber.
 63. The air cleaner as defined inclaim 1, wherein said housing includes a lower section and an uppersection, said upper section having an exterior surface, a bottom edgeand an interior compartment; said lower section having a base, a topedge, an outer surface, an inner surface and an inner compartment; saidlower and upper section connected together by a sealing arrangementwhich connects said upper section bottom edge to said lower section topedge, said lower section base includes a damper to reduce noise duringoperation of said blower, said damper including a material selected fromthe group consisting of rubber, plastic, foam and combinations thereof.64. An air exhaust arrangement for a blower that generates lessvibrational noise during operation comprising an outer peripheral edge,a blower, a blade rotatably connected to said blower, and a blowerexhaust housing having an air passageway for the expulsion of air fromsaid blower to the outer peripheral edge, said blower exhaust housingincluding a plurality of arcuate vanes radiating outwardly from saidblade, each of said vanes having a length and two ends, each of saidvanes having a radius of curvature over at least a section of saidlength of said vane, said first end of said vane positioned closer tosaid blade than said second end of said vane, said arcuate vanesdirecting said air in a substantially unobstructed manner to said outerperipheral edge, said second end of at least one vane extending to saidouter peripheral edge of said housing, said arcuate vanes are positionedabout said blade to reduce the amount of noise below about 20 KHz. 65.The air exhaust arrangement as defined in claim 64, wherein said arcuatevanes are positioned about said blade to reduce the amount ofvibrational noise during operation of the blade.
 66. The air exhaustarrangement as defined in claim 64, wherein said arcuate vanes arepositioned about said blade non-symmetrically relative to said blade.67. An air exhaust arrangement for a blower that generates lessvibrational noise during operation comprising an outer peripheral edge,a blower, a blade rotatably connected to said blower, and a blowerexhaust housing having an air passageway for the expulsion of air fromsaid blower to said outer peripheral edge, said blower exhaust housingincluding a plurality of arcuate vanes radiating outwardly from saidblade, each of said vanes having a length and two ends, each of saidvanes having a radius of curvature over at least a section of saidlength of said vane, said first end of said vane positioned closer tosaid blade than said second end of said vane, said arcuate vanesdirecting said air in a substantially unobstructed manner to said outerperipheral edge, a plurality of said arcuate vanes being positionedabout said blade non-symmetrically relative to said blade.
 68. The airexhaust arrangement as defined in claim 67, wherein each of said arcuatevanes having a length, at least one of said arcuate vanes having alength that is different from the length of at least one other arcuatevane.
 69. The air exhaust arrangement as defined in claim 67, whereineach of said arcuate vanes has a radius of curvature over at least aportion of the length of said arcuate vane, at least one of said arcuatevanes having a radius of curvature that is different from the radius ofcurvature of at least one other arcuate vane.
 70. The air exhaustarrangement as defined in claim 67, wherein at least two of said arcuatevanes having two ends, said first end positioned closely adjacent tosaid blade and said second end positioned at least closely adjacent tosaid outer peripheral edge of said blower exhaust housing, at least oneof said arcuate vanes having a first end spaced closer to said bladethan said first end of at least one other arcuate vane.
 71. The airexhaust arrangement as defined in claim 67, wherein at least two of saidarcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said blower exhaust housing,said first end of at least one of said arcuate vanes spaced a greaterperimeter distance about said blade from said first end of an adjacentarcuate vane than the perimeter distance about said blade from saidfirst end of another adjacent arcuate vane.
 72. The air exhaustarrangement as defined in claim 71, wherein said first end of at leastone of said arcuate vanes spaced a greater perimeter distance about saidblade from said first end of an adjacent arcuate vane than saidperimeter distance about said blade from said first end of anotheradjacent arcuate vane.
 73. The air exhaust arrangement as defined inclaim 67, wherein at least two of said arcuate vanes having two ends,said first end positioned closely adjacent to said blade and said secondend positioned at least closely adjacent to said outer peripheral edgeof said blower exhaust housing, said first end of each vane has an endregion, said end region of at least one of said arcuate vanes has agreater thickness than the thickness of said end region of at least oneother arcuate vane.
 74. The air exhaust arrangement as defined in claim67, wherein at least one of said vanes overlaps at least a portion of anadjacently positioned vane.
 75. The air exhaust arrangement as definedin claim 67, wherein said blade includes an axis of rotation, at leasttwo of said arcuate vanes having two ends, said first end positionedclosely adjacent to said blade and said second end positioned at leastclosely adjacent to said outer peripheral edge of said blower exhausthousing, said first end of at least one of said arcuate vanes includinga front face having a sloped surface along at least a portion of saidfirst end, said sloped surface have an angle that is nonparallel to saidaxis of rotation of said blade.
 76. The air exhaust arrangement asdefined in claim 67, wherein said blade includes an axis of rotation, atleast two of said arcuate vanes having two ends, said first endpositioned closely adjacent to said blade and said second end positionedat least closely adjacent to said outer peripheral edge of said blowerexhaust housing, said front face of said first end of each of saidarcuate vanes having an angle that is nonparallel to said axis ofrotation of said blade, said angle on said front face of said first endof at least one arcuate vane being different from said angle on saidfront face of said first end of at least one other arcuate vane.
 77. Theair exhaust arrangement as defined in claim 67, wherein at least two ofsaid arcuate vanes having two ends, said first end positioned closelyadjacent to said blade and said second end positioned at least closelyadjacent to said outer peripheral edge of said blower exhaust housing,said second end of at least one of said arcuate vane spaced a greaterperimeter distance about said outer peripheral edge from said second endon an adjacent arcuate vane than said perimeter distance about saidouter peripheral edge from said second end of another adjacent arcuatevane.
 78. The air exhaust arrangement as defined in claim 67, wherein atleast two of said arcuate vanes having two ends, said first endpositioned closely adjacent to said blade and said second end positionedat least closely adjacent to said outer peripheral edge of said blowerexhaust housing, said first end of at least one of said vanes beingtapered.
 79. The air exhaust arrangement as defined in claim 67,including at least one air flow distributor positioned between at leasttwo of said arcuate vanes.